Control for two-engine vehicles



p 14, 1954 M. M. DEAN ETAL 2,689,013

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Sept. 14, 1954 M. M. DEAN ETAL CONTROL FOR TWO-ENGINE vsmcuas l2 Sheets-Sheet 12 Filed March 28. 1947 Patented Sept. 14, 1954 CONTROL FOR TWO-ENGINE VEHICLES ilo Dean, Palatine, and Nils A. Thunstrom, Chicago, 111., assignors to The Greyhound Corporation, Chicago, 111., a corporation of Delaware Application March 28, 1947, Serial No. 737,976

so Claims.

This invention relates to improvements in power applications in the automotive vehicle field. The invention also relates to improvements in methods of engine control. The invention further relates to improvements in power plant structures as well as in structures by which to control said power plant structures. At present the invention finds its most valuable application in the use of two engines and their control for driving an automotive vehicle. The invention has for a special object to provide a power plant, and method and means for control the cof tor operating a bus and its accessories, very efliciently and economically. A particular object is to drive the accessories at or near their most economical speeds, irrespective of greatly varying vehicle speeds.

Another object of the invention is to provide means by which two engines may simultaneously power a vehicle, with said means so operable that when one of th engines, herein sometimes called the first or main engine, is operating at any speed to power the vehicle, power from the other or second engine can be automatically transmitted to assist the first engine. Another object is to provide means which automatically. prevents the vehicle or the first engine from driving the second engine. Another object is to obtain smooth, synchronized transmission of additional power by one engine to the wheel-driving shaft, while that shaft is being driven by another engine. Another object is to obtain smooth transmission of power for vehicle drive under all the varying speed and load conditions which are met with in operation of automotive vehicles, particularly buses. Another object is to provide auxiliary engine controlled means acting through an overrunning clutch to cause the overrunning clutch to automatically transmitpower to the wheeldriving shaft when auxiliary engine speed rises to some predetermined speed. Another object is to provide means by which power from an auxiliary engine can be transmitted for driving the vehicle just as soon as, but only when, auxiliary engine speed rate has risen to (or overtaken) speed rate of a main engine. while said main engine is driving the vehicle. Another object is to provide means to allow the auxiliary engine to be used. to alone propel the vehicle, when the main engine is inoperative.

In order to better understand how the present invention has solved some of the problems incident to bus operation, it will be helpful to discuss the present practice, and to compare that practies with the practice proposed herein, regarding the arrangements of the power plants and the methods of controlling them for driving a vehicle, or for driving a vehicle and the accessories.

Bus operation presents special problems, operating as they do over all sorts of roads and under all sorts of weather and road conditions. The solution of such problems presents special difficulties in relation to limitations of space, weight, weight distribution, and fuel economy.

In view of the increasing demand for more power for propelling buses and their accessories, it has heretofore been found necessary to provide single engines of greater and greater horsepower. Such engines are special, are expensive to buy and to maintain, and are heavy and difficult to handle, either for original assembly or for disassembly.

When one large all-purpose engine is used, to drive the bus and the accessories and if the engine fails, the bus is stalled and of course the accessories are also rendered inoperative, which means that there is no compressed air, light, airconditioning, heat, etc. Moreover, when a single large engine is used there is low fuel economy when cruising as on level roads, because the engine is operated at an uneconomically low load factor. The greatest fuel economy can be had when an engine is operated at a load factor of about seventy-five to one hundred per cent.

When using a single engine directlydriving the accessories, accessory speeds fluctuate with engine speed fluctuations. When the single engine is idling, the accessories may not be driven at their required speed, and poor fuel economy results if fractional throttle operation of the single engine is necessary to obtain and maintain proper accessory speed. In addition, directly connected accessories are subject to engine vibration and this results in engine unbalance and rapid wear of driving elements, such as timing gears, etc. Also, the large engine must be of special make and oversize, and requires a special line of service parts and tools. These large engines are much more expensive than medium-size engines. Moreover, one large engine mounted transversely of the bus behind the rear axle necessitates an angle drive connection between th transmission and the differential, and involves diflicult mounting problems. Weight distribution transversely of the vehicle cannot be most advantageously obtained.

Where one large engine is used only for propelling the vehicle and one small engine is used only for driving the accessories, failure of either engine means total stoppage of the vehicle or of the accessories. In this case also the accessories are subjected to engine vibrations and they may cause engine unbalance. Where two different sizes of engines are used, two different lines of service parts and tools are required and the charactor of each service operation is difierent.

Now in bus operation even small economies are very important, but the invention herein provides relatively large economics. as will hereinafter appear. We propose to overcome the above objections to the use of one oversize special make all-purpose engine, or to the use of one large engine for vehicle drive only and one small engine for accessory drive only, by providing two medium-size preferably standard-type engines of substantially the same horsepower, and each capable, under favorable conditions of simultaneously driving both the vehicle and the accessories. But we normally use only part of the power of one of the engines to drive the accessories at constant speed and with good fuel economy, and use the other engine only for driving the vehicle under normal or favorable load and road conditions, also with good fuel economy. We also provide means under driver control whereby the surplus power of the accessory-drive engine can at the will of the operator be promptly, automatically and effectively transmitted for assisting the other engine in driving the vehicle. The selective transmission of surplus power is in part, uniquely accomplished herein through a single-throttle pedal during natural forward motion of the pedal. In this respect throttle pedal operation is of a type familiar to all drivers, so that no special thought or unusual act is necessary on the drivers part to cut-in or cut-out the power of the auxiliary engine, for use in vehicle propulsion.

Selective means are further provided whereby if either engine fails the other engine can in an emergency simultaneously drive the vehicle and the accessories. A feature is that none of the accessories are mounted on the engine but have their power elements mounted, all or in part on the same but separate support, which support encloses intermediate accessory drive mechanism, which may include speed-change devices.

With our invention, ordinary cruising can be had at an economical load factor, with resultant good fuel economy. In the preferred form of our invention the auxiliary engine operates at an economically high load factor and therefore with good fuel economy, at relatively low constant speed on an engine governor regulated carburetor for powering the accessories, thus requiring no manual attention except for starting the engine. The same engine is also operated on another manually controlled carburetor for power outputs above that required for driving the accessories,

when transmission of its suplus power is needed to assist the main engine in powering the vehicle.

In one phase of our invention accessory speed only varies under emergency conditions, that is. when the auxiliary engine is being accelerated or operated in its higher speed and power range. In another phase of the invention the intermed1- ate accessor drive mechanism, above mentioned, can automatically operate to substantially prevent undue speed accelerations of the accessories when the auxiliary engine is speeded up.

By the use of an engine governor-regulated carburetor on the auxiliary engine, accessory speed is automatically kept substantially constant. We provide for the manual interruption of transmission of power to the accessories on failure of the accessories per se, and also provide for driving the accessories by means of the main engine in case of failure of the auxiliary engine.

The usual manual means are herein provided for controlling the main engine clutch, and additional means, associated with the manual control means, is provided for locking the main engine clutch in open position in case of main engine failure. In case of such failure surplus power of the auxiliary engine can be transmitted for driving the vehicle, while at the same time this engine can drive the accessories.

By the use of two duplicate medium-size engines the same can be mounted symmetrically, one at each opposite side of the longitudinal center line of the bu so that straight drive to the transmission and differential is possible, and so that power plant weight is symmetrically distributed in relation to said longitudinal center line of the vehicle. The line of service parts and tools are identical for both engines and each service operation is of the same character. The smaller, lighter engine units are easier to assemble and disassemble, and the smaller engines and their parts are more readily available, and they are cheaper.

There are several structures herein which may per so be considered to constitute distinct phases of this invention, usable in various combinations and subcombinations, and among these phases are: The use of automatic means, such as a centrifugal or equivalent clutch on one of two engines for automatically power-connecting that engine to drive a common shaft driven by the other engine, only when the engine speed exceeds some predetermined minimum; the driving of a common shaft by one or two engines separately or by both simultaneously, and in which the common shaft is connected at one end to the input shaft of a transmission, from the output side of which the wheels are driven, and/or in which the other end of the common shaft is connected with the rotor of an hydraulic retarder system; the specific structure by which the engines are connected with the common shaft including hollow shafts and the use of any suitable types of clutches for transmittably connecting those hollow shafts with the engines; the specific bearing structure arrangement of the hollow shafts in relation to the crank shafts of the engines; the arrangement of additional shafts passing through the hollow shafts and connected with the engine cranks; arrange ment of the bearings for the aforesaid shafts which assures maintenance of substantial alignment even in the presence of bearing wear; the use of two carburetors. one for each engine, and controlled from a common throttle pedal to oper ate one engine substantially within its total power range and to cut-in power of another engine to assist the first engine; the arrangement whereby two engines can separately or together power a single shaft while either powers another shaft; the stepping of the hollow shafts in the crank shaft and in a casing which connects the engines; the specific relations of the clutches to the hollow shafts for applying the power of either or both engines to a common shaft; the specific use of a centrifugal clutch acting through an overrunning clutch upon a shaft which powers vehicle wheels and which shaft is also powered by another engine, thus obtaining free wheeling for one of the engines; the use of a single engine controlling the speed of a centrifugal clutch which acts through an overrunning clutch to transmit power from the engine and at the same time to allow free wheeling; the bevel gear drive in relation to hollow shafts,each clutch-controlled from its engine; and the use of part of the power of one of the engines for driving the accessories, and the automatic coupling of its surplus power for driving the vehicle.

Other objects, features, and advantages of the invention will be referred to in the: description of the drawings, and in said drawings:

Fig. 1, is a somewhat diagrammatic plan section, showing the general arrangement of certain of the elements concerned in carrying out important phases of the invention herein;

Fig. 2 is a side elevation showing general relations of certain of the elements as applied to a wheeled vehicle;

Fig. 3 is a top plan view, with the tower mechanism omitted;

Fig. 4 is a vertical section through the main and tower casings, taken transversely of the vehicle and approximately on line 45 of Fig. 3 and looking forwardly;

Fig. 5 is a vertical sectional elevation through the main and tower casings taken longitudinally of the vehicle and approximately on line 5-5 of Fig. 4;

Fig, 6 is a schematic view of the clutch shift mechanism of Fig. 5, viewed from the position of line 86 of that figure;

Fig. '7 is a vertical section through the main casing and through the flywheel housing of the auxiliary engine, illustrating the automatic clutch mechanisms;

Fig. 8 is a detail section of the overrunning clutch taken approximately on line 8-8 of Fig.

Fig. 9 is a face view of the centrifugal clutch, I

viewed generally from the position of line 9-9 of Fig. 7, but in which, to facilitate illustration, parts are broken away and sections are taken, in different vertical planes;

Fig. 10 is a detail view of the bottom part of 1 Fig. '7, showing one of the centrifugal mechanisms in clutch-in action;

Fig. 11 is a vertical section through the main casing and the flywheel housing of the main engine, illustrating the manually operable engine clutch;

Fig. 12 is a somewhat diagrammatic view, illustrating the means for controlling the large carburetors, respectively of the main and auxiliary engines, from a single pedal;

Fig. 13 is an elevation partly in vertical section taken approximately on line I3l3 of Fig. 12;

Fig. 14 is a plan view of the structure of Fig. 13;

Fig. 15 is a detail plan view of the manual control device for the clutch of the main engine, and associated means for locking the clutch in open position;

Fig. 16 is a vertical section taken approximately on line Iii-16 of Fig. 15;

Fig. 17 is a vertical section taken approximately on line l'|--l'| of Fig. 15;

Fig. 18 is a side elevation of a portion of the auxiliary engine showing its small carburetor and linkage means by which the said carburetor is engine-regulated;

Fig. 19 is a somewhat diagrammatic vertical cross-section on line l9-l9 of Fig. 18 further illustrating the linkage means; and

Fig. 20 is a section showing part of the rotor of the hydraulic brake means in relation to its stator.

GENERAL SCHEME Now referring to the drawings, and to certain important broad phases of this invention. Figure l is somewhat diagrammatic, and its elements represent: Means by which either engine can selectively power a common ormain shaft, which fall 6 shaft is mounted on a casing, which in turn rigidly connects the engines, by means of their flywheel housings; means by which shafts for transmitting power from the. engines to the com mon shaft can be power-connected, with respective engines; means by which these shafts are held in axial alignment with. the crank shafts by being stepped atone end on the corresponding crank shaft and at the opposite end stepped in bearings of the casing which connects the engine flywheel housings; means by which either engine can independently drive an accessory drive shaft; and the means by which the accessory drive shaft can be power-disconnected from 1 both engines in the case where there is a breakdown of accessories demanding their release, so that either or both engines can operate without rotating the accessory drive shaft.

The numeral l indicates a shaft which, in the preferred form of the invention, drives the wheels of a vehicle. This shaft is also referred to as the main shaft and is connected at its forward end with the power input shaft 2 (see Figs. 3 and 5) of any suitable form of transmission mechanism generally indicated at 3. The transmission output shaft (not shown) is suitably connected through a propeller shaft 4 with any preferred rear axle drive mechanism generally indicated at 5, for Wheels 6. A propeller shaft brake has been indicated at 1. To the opposite end of the shaft l is connected the rotor shaft 8 of a hydrodynamic brake mechanism, the casing of which is indicated at 9. The driving of the rotor of this brake in the manner shown is believed to be new, and has advantages, later explained.

Arranged at opposite sides of the shaft I and with their crank shaft axes aligned in a direction transverse to the shaft I and to the long axis of the vehicle, is an engine l0 herein designated as the main or first engine, and an engine It designated as an auxiliary or second engine adapted for driving vehicle accessories and for assisting the main engine in driving the vehicle. These engines are preferably standard, may be of any preferred and suitable type. The crank shaft for the main engine I0 is indicated at 12 and the crank shaft for the auxiliary engine H is indicated at l3.

When we speak of engines of the automotive type, it is to be understood that the engines in clude all of the usual elements needed for their operation. It will be further understood that, although not all shown, the necessary controlled rods and levers are provided for operating the engines from the drivers station.

The engines are cross-connected by a main casing generally indicated at l5, which performs important functions herein. The casing provides opposite front and rear bearings I5 and H for the main or wheel driving shaft I. This casing also provides means rigidly but separably connecting the engines, and the transmission and part of the hydraulic brake mechanism is connested to it, see also Figure 5.

The main casing l5 subserves various functions, each of which is important in the present com bination. It provides means rigidly connecting the engines together, it provides rigid bearings for shafts which are directly connected with the crank shafts of the engines; it provides means to which the casing of a suitable transmission mechanism can be attached; it provides means to which a casing for the rotor of a hydraulic brake system can be attached; and it provides means for supporting a casing having therein selective accessory takeoff drive mechanism. The main casing also provides terminal chambers or bells as connecting elements adapted to house part of the clutch mechanism of each engine.

Shaft I is provided with a bevel gear I8 meshing on the main engine side with a bevel gear I9 and on the auxiliary engine side with a bevel gear 20. The bevel gear I9 has a tubular shaft 22 which is stepped in a bearing 23 of the main casing I and is also rotatably stepped in a bearing 24 of the crank shaft I2 of the main engine. This shaft 22 is therefore so arranged that it can rotate independently of the main engine, and so that the main engine can operate without rotating it. In order to transmit power from the engine to the hollow shaft 22, a clutch designated 25 is provided. This clutch is associated with the flywheel of the main engine (see Fig. 11). A clutch disk member 26 is attached to a sleeve which is keyed to tubular shaft 22 as at 21. This clutch is more fully described herebelow. The clutch may be of the ordinary type, and is manually controlled by the driver through the usual foot pedal (not shown) in the usual manner of clutch control for engines of the automotive type. In the preferred form the bearing 23 is a double row roller bearing structure, and the bearing 24 is of ball-type The same types of bearing are used for the shaft of gear 20, now to be described.

The bevel gear 20 has a tubular shaft 30 stepped bearings 3| of the case I5, and in bearings 32 of the crank shaft I3 of the auxiliary engine. In this case also the auxiliary engine can run without operating the tubular shaft 30. The shafts I, 22, and 30, are thus so geared together that rotation of one of the shafts, rotates the other two.

It is a feature of this invention that both engines are controlled from a single pedal, and that when that pedal is depressed to a certain degree, there results an automatic transmission of auxiliary engine power to the vehicle wheels. Moreover this automatic transmission occurs when auxiliary engine speed is the same as the speed of shaft I,whether that shaft is being driven by the vehicle or by the main engine. This makes for smooth, non-jerky transmission coupling action. mechanism is provided which in the preferred embodiment includes a centrifugally controlled component operating through an overrunning clutch component to automatically couple or transmit auxiliary engine power to shaft 30, gears 20, and I8 to shaft I, when auxiliary engine speed exceeds a predetermined speed. This automatic mechanism is generally designated 33, and is associated with the flywheel of the auxiliary eng'ine (see Figs. '1, 8, 9 and for details). A clutch disk indicated 34 is secured to the outer race of an overrunning clutch designated 35, the inner race of which clutch is keyed to tubular shaft 30. Centrifugally acting weights 36 cause the centrifugal clutch to take hold or clutch in, as soon as engine speed exceeds a predetermined speed, as will be more particularly described herebelow. Thus far there has been described a mechanism including a wheel-driving shaft which can be driven by either engine or by both engines simultaneously, so that the auxiliary engine can assist the main engine in powering the vehicle wheels.

By having the main shaft I and the two hollow shafts 22 and 30 permanently geared together For this purpose an automatic clutch D so that rotation of any one of the three shafts rotates the other two, no extra clutch is necessary. Only two clutch means are used, one for the main engine manually controlled, and the other for the auxiliary engine, automatic in action.

Another important feature of this invention relates to the means (see Fig. 1) by which either engine can power a second or output shaft 31, from which all of the various vehicle accessories can be operated or powered. The specific structure is claimed. Thus, in one phase of the invention part of the power of the auxiliary engine is normally used for operating the shaft 31 or its equivalent, and part used for assisting the main engine III to power the shaft I.

To power the output shaft 31 for the accessories, the main engine has a shaft 38 which is keyed as at 39 to the crank shaft I2, and this shaft 38 passes through the hollow shaft 22 and is stepped in a bearing 40 (shown only in Figure 1) carried by the hollow shaft 22. The specific arrangement of this bearing 40 for shaft 38 is like that shown in Figs. 4 and 7 for the functionally similar shaft 41 of the auxiliary engine. The inner end of the shaft 38 has a spur gear 4I meshing with an idler gear 42, in turn meshing with an idler gear 43, in turn meshing with a gear 44 which is rotatable on the output shaft 31. This outer terminal gear 44 of the train has a clutch member 45 engageable by a shiftable tubular clutch element 46 splined to the output shaft 31. In Fig. l the shiftable clutch is released from the clutch element member 45.

Stepped in the crank shaft I3 of the auxiliary engine is a shaft 41 functionally similar to the shaft 33. The shaft 41 is keyed as at 48 to the crank shaft I3 and passes through the hollow shaft 30 and is stepped in a bearing 49 in said hollow shaft, see Fig. '1. Fixed to the outer end of the shaft 41 is a gear 50 meshing with an idler gear 5I, in turn meshing with a gear 52 rotatable on output shaft 31. This gear 52 has a clutch member 53, and in the drawing the shiftable clutch member 46 is engaged therewith so that shaft 31 will be driven by the auxiliary engine II. The shift clutch member 46 may assume a neutral position, in which case the output shaft 31 will not be driven.

The gear trains shown in Fig. 1, functionally correspond to means by which the power of either engine can be transmitted to a common power output shaft from which the accessories are driven, either directly, or preferably through intermediate gearing. However, the preferred means by which the shaft 31 is driven and controlled is shown in Figs. 4, 5 and 6. The output shaft 31 is always driven in the same direction, whatever engine may be powering it, and this is also true of shaft I. In all cases the rotation of the output shaft can be stopped by shifting the lever shown in Fig. 6 to the central or neutral position in which neither clutch is engaged. In both cases the output shaft 31 can be operated from either engine. The unique specific driving train structure of Figs. 4 and 5 is described herebelow and is claimed because of its structural simplicity, simple assembly characteristics and mechanical effectiveness.

Hydraulic-retarder connecting scheme The present invention also provides a new method (see Fig. 20) of connecting the rotor 54 of a hydro-dynamic brake mechanism (see Figs. 1, 2, 3), the rotor casing of which is indicated at 9. The liquid supply intake side of the rotor casing is indicated at 55 and the discharge side at 56, see Fig. 2. The stator as indicated at 51, and 58 indicates suitable means connecting the shaft l to the rotor shaft 8. Any suitable form of hydro-dynamic braking device, such, for example, as that shown in Ramey Patent 2,287,130, can be used herein. Since no claim is'made to this retarder system per so, no part of the system has been shown other than the rotor, rotor casing, stator, and intake and discharge ports of the rotor casing. The operations of such systems well known.

Hydraulic retarder units have heretofore been used on heavy duty (freight-hauling) automotive vehicles having the engine in the front and having the usual rear axle drive, but in that use the rotor of the unit is connected to the propeller shaft so that shaft continuity. is throu h the rotor of the unit. Under such oondltions'when the vehicle speed is substantially reduced the ejfiioiency "of the retarder unit falls" off rapidly and finally. atlow vehicle speed the r'e is no effective'braking action. In our scheme 3on do not connect the rotor to a shaft whichis driven from the'output shaft ofthe'transniissionf Shaft l %s coupled at one end with the rotor shaftfiasat g .and at the other end (see Fig. 5) withIt'he pwer input shaft 2 of a conventio aloi' other auntie .e'rsgsmissmn mechanism." Jththi's'ap- ,plicfition" through the transmissionthe operator shiftiiiglltda low r 'g'eafllallow fo'it'sl'ifii- 1 hfiice speed a: a ea -t are etflcleigse ngreatl reduced.

flaring described the general arrangement of .v'v'e win now proceed as de enbe the new d'specific constructions .of various ielenie ts, certain broad functions'of which have ,heen..above referred to.

AU'I'QMATIC CLUTCH RAF-ANS The automatic clutch means new to be dein detail may have uses otherthan that shown herein. It is particularly useful as an element in our structure, wherein two engines are used,,and in which part of the power of one of the engines is used to power the accessories of the yehicle and in which its surplus power can heintermittently used to assist the other engine in the vehicle wheels.

While the primary concern of the present inrention is to provide a superior kind of power plant andcontrol therefor, yet we believe that theas'sociation of any clutch, including a centrifpgal'ciutch, with an overrunning clutch, to harethe former control the latter for automatically obtaining power transmission by an engine to a shaft, provides a new device or elemerit which can be used in environments or com- 'binations differing from our principal use herein. new element can be used on any'eng lne in which it is desired to obtain automatic transmission of power, or which is adapted to be operated at low speed for one purpose and at a higher speed for another purpose. The transmission clutch means of this inven ion can also be used in relation to one of a pair of power-generators so 'that'when the load of a first generator becomes too great for its power capacity, a second genorator can be caused to couple automatically its power tothe first generator. Thus, a standby power. unit can be used to augment.the power of apr m y po er u it.

Now referring to Figs. '1 to 19. nclusive. To power the hollow shaft 19123 the as! s ans a. some ee m s surrounds and acts upon the tubular shaft 30. This multiple automatic clutch means comprises two clutch components or elements, one acting through and in partmou'nted 'on the other, one a centrifugal clutch, and the other an overrunning clutch. The main casing (5 has a belllike housing gt whichisbolte'dto the flywheel housing Bl of the auxiliary engine II. The flywheel'is indicated t'gg and it is'suitably bolted 'to the crani; shaft as shown.

Overrunning clutch component Splined to the hollow shaft 30 (see Figs. 7 and 8) as at 53 is a tubular inner race fit of the overrunning clutch. A series of clutch blocks 65 are adapted to rock and obtain wedging clutch-in ac- *lbfl against the outer surface of the inner race and the inner surface of an outer tubular race h ut r ag 6.6.1. mo nt on w a bearing structures 6 1 carried by the inner race (it. In Fig. 8 the clutch blocks are in release p ion e. mot ve spee o the outer race lit becomesgreater than that of the inner race the blocks are rocked in clockwise direction and clutch-in action occurs and the hollow shaft 3 1S 1n c ockw e direction. as v w m th l ft o F gu e .1

ach ai -block l teral ooves .60. o in each opposite side, and circular constrictive S in 3 li i the ooves .68. one at each sid of the circular serie of blocks- This cl tch chanism. pe e isnotclehned here ut only t partic lar functional relation-to the other e ements ofthe. combination. Any suitable tim of ove u mns c utch can be used.

henut r t bular e ement or race .65 of the u ins lu ch a peripheral diski flange 12 to which is suitably attached a clutch plate 13, ashes} ,shqwnin ,Fig. .7. This clutch plate. ca ie suitable friction rings 1.4 at opposite sides, respectively for engagement with the corresponding clutch surface 15 of the engine flywheel 62 and with the clutch surface 16 of a clutch ring 11 of a centrifugal clutch mechanism now to be described. It is noted that the overrunning clutch, with its clutch disk. is a unit which can be separately assembled on shaft 30, and this is also true of the centrifugal clutch unit now to be described. The entire overrunning clutch unit withits friction disks is free to move axially in either'dir'ection on' the shaft 30, for engagement disengagement of its disks M with the'olutch ui-races" 115,13.

Centrifugal clutch component The centrifugal clutch, as a unit, includes a casing onwhich th'-parts'are mounted, which casing is secured'to the 'engine'flywhel fifby bolts 81', sdftliat speed controls clutch operation. lh'e'caisihifi? h S'an annular hub 02 through whi'chthe shaft .30 freely passes. Between theinner's'idepf the casing 80 and the clutch plate It, are'fdisposed two'rings, one the clutch ring 11 pr viously mentioned, and the other a power, adapted to be moved towardthe clutohr ,"".1 l, a;nd.to apply a proper pressure thereto hrough 'a circular series'of compression ,8}: is Q4 only one of which is shown iniFigL' 'L ower for closing the clutch is applied through these springs -Sockets in ring 83 receive springs they are centered aroundproiectipiis' 'ff theriiig' I1 as shown. The

ring 83 isfiiw'ifl' six recesses 85 in its outer of toggle systems ueesn wu l -sl e The rings 11 and 83 are mounted on the casing 80 for axial movement and for rotation with the casing 80 as rotated. by the auxiliary engine flywheel 62. Means is provided for retracting the rings, to the clutch-open position shown in Fig. 7. Means is also provided for adjusting the tension of the springs 84. The means for retractin the rings includes six bolts 81 each having threaded engagement as at 06 with the clutch ring I1. The power ring is slidable on these bolts, the ring having cylindrical bores for this purpose. On each bolt is an adjustable stop nut 89 engageable with suitable threads 01 the bolt. By adjusting these nuts the tension of the springs 84 can be adjusted. The bolts 81 extend outwardly through thimbles 90, one thimble for each bolt. Each thimble is mounted in an opening of the casing 80. A spring 92 surrounds each bolt and is contained in the thimble. Each spring is under compression between the inner end of the thimble and a spring tension adjusting nut 93 threaded on the rod 81. The six springs act to retract the rings, that is. move them to clutchout position, and also to yieldably force wedge surfaces 95 of wedge plates on the ring 83, toward wedges 96 and toward companion wedge surfaces 9! of plates carried onthe inner face of the casing 60, as will be more fully described hereafter.

Rings 11 and 83 are centered and connected to rotate with the casing 80, by means of six bolts 98 passing through the wall of the casing 80 and held by suitable nuts, and having rectangular enlargements 99 which abut and project radially from the inner surface of said casing 60. Each enlargement 95 is disposed between and has opposite faces slidably engaged with opposed flat surfaces of a pair of axially extending lugs I of the ring IT. The outer surfaces of each pair of lugs I00 are similarly slidably engaged with the opposed surfaces of a. corresponding radial notch IOI of the ring 83. Thus, the rings are centered and are free to move axially but must rotate with the casing 80 and, therefore, with the flywheel.

Centrifugal clutch control mechanism The centrifugally operable mechanism for acting automatically to force the ring 83 toward the ring 17 to cause the latter to clutch-in by engaging the clutch ring I4 to press the opposite ring I4 against flywheel surface Ii, includes springs and weights and the wedges.

Referring to Figures 7 to 10, inclusive. There are six arcuate wedge plates I04, each providing a wedging surface 96, and these plates are removabLv secured as by screws to the ring 63. Six corresponding, and opposed and arcuate wedge plates I06 provide the wedging surfaces 91, and these plates are detachably secured by screws to the inner face of the casing 80. There are also six wedge blocks 06, one for each pair of plates, and each wedge is separately controlled by a weight-actuated toggle mechanism. For this control each wedge 06 has pivoted thereto at opposite sides, as by a pin I06. two links I01 (see also left side of Fig. 9). These links I0I are in turn pivoted by a pin I08 to three links, two of which are indicated at I09. The links I09 are in turn pivoted by a pin IIO to an inner radial pro- .iection III of the hub 82 of the casing 80. The pin I08 forms a pivot for one end of a third link H2 which passes freely through an opening H3 in the casing 86. The link H2 is pivoted by a pin II4 (see right side of Fig. 9), between fork ,gal action, as when the speed of the engine is sufllciently high. It may be assumed as an example only, that the weights begin to act on the toggles to move the wedges to cause clutch-in action, when auxiliary engine speed exceeds 900 R. P. M. which speed is substantially below its maximum speed rate which may be 2600 R. P. M.

Pivotally connected by a pin I20 to the long arm II! of the bell crank lever are two links I2I.

The upper ends of these links are pivoted to a pair of pins I23. each integral with and projecting laterally from a slide head I24. Each head has a spring-centering projection I25, an the heads are slidably guided on two parallel rods I26. Each rod (see middle of Fig. 9) is stepped in an opening I21 of a radial projection of the hub B2, where it is held by a pin. At th Oppo i end each rod I26 is stepped in a sleeve I28 exteriorly threaded as at I29 and having a projection I 30 engaged in an opening ill of the shelf I32 of a bracket I33 suitably bolted to the outer face of the casing 80. Each rod I25 passes through a. tubular spring guide I34. Each guide is in threaded engagement with the threads I29 of sleeve I28. The lower terminal of the spring uide is flanged as at I35. A compression spring I36 surrounds each rod I26 and guide I34, and at one end abuts the flange I35 and at the other end engages around the centering projection I25 of the slide head I24 and abuts the head and forces it to its uppermost position against a stop surface I31. The springs thus act, through the link system, to retract the wedges to the position shown in Fig. '1, and the springs are under initial compression for this purpose. The weights move under centrifugal action against spring tension until they finally assume the position of Fig. 10. At the end of this movement the links I 01 and I09 have assumed the aligned position of Fig. 10, at which position wedging action is at its maximum, and the clutch is fully engaged. Outward motions of the weights are limited, as shown, by the engagement of a given weight with an adjustable stop screw I88. Here it is to be noted (see Fi 10) that in this limit or clutch-in position the short arm I I 6 of the bell-crank lever has entered between the links I2 I, the total width of the arm I I5 in relation to the axial spacing of the links permitting this entry.

The action of the centrifugal clutch is as follows: When the parts are positioned as in Fig. 7 and when engine speed rises sufllciently, the weights :6 act centrifugally against the action of the springs I05 to move the toggle system to straighten the toggles and drive the wedges outwardly in radial direction, see Figure 10. This radial drive of the wedges results in movement of ring 88 to the left, during which movement the circular series of springs 64 are compressed driving the disk 11 against the friction rings 14 and in turn driving these rings toward the surface I5. of the flywheel.

when auxiliary engine speed is sufflciently reduced the centrifugal clutch moves from its posiaeaaeis tion of Fig. again to the position of Fig. '7. This involves movement of the wedges in an inward radial direction, and decompression of the springs 84, and movement of the rings 83 and 11 to 'the right under action of the springs 9-2. With this movement the plates I4 are released and the outer race of the overrunning clutch is no longer positively driven.

No matter what kind of transmission clutch may be used to cause engine power to be transmitted through the overruning clutch, automatic transmission of engine power to shaft 30, can only occur when outer race speed exceeds inner race speed, and the shaft 36, can never drive the auxiliary engine through that clutch when wheeldriving shaft speed is greater than outer race speed. If the speed of shaft 38, and therefore the speed of the inner race, exceeds that of the speed of the outer race (even though the centrifugal clutch is closed), the auxiliary engine cannot be driven through shafts I, and Si! whether they are driven by the vehicle or by the main engine. The wheel-driving shaft I, is free to rotate in wheel driving direction when the transmission clutch of the auxiliary engine is out and the auxiliary engine is operating, and when said transmission clutch goes in, no drive of the shaft I through the overrunning clutch can occur until engine speed is such as to rotate the outer race at greater speed than the inner race or shaft speed. Thus auxiliary engine power can be transmitted to the shaft I smoothly and without jar. Moreover, free wheeling through shaft I, in relation to the auxiliary engine, can be had at all times except when the auxiliary engine drives the outer race of the overrunning clutch at a greater speed rate than that of theinner race.

It may be said that one or the other of the clutch components acts to prevent one engine from driving the other, and that both components must act together to transmit power from the auxiliary engine to assist the main engine in driving the vehicle wheels.

We have thus provided for automatic release by means of the overrunning clutchwhen main shaft speed is greater than any auxiliary engine speed, which is 'above accessory drive speed, and we have also provided for automatic release by a centrifugal clutch. We have also provided for automatic power transmission when auxiliary engine speed is equal to or greater than main shaft speed. The above function can also be performed by a suitably controlled conventional clutch, in conjunction with'an over-running clutch. The advantage of the use of a centrifugal or other suitably controlled clutch in association with an overrunning clutch is that auxiliary engine speed can control both power transmission to and auxiliary engine release from, the main or vehicle driving shaft, with the advantages above enumerated.

TOWER CASING AND MECHANISM THEREON The mechanism now to be described (see Figs. 4, 5 and 6 is a unit, and'includ-es a casing which is detachably secured to the top of the main casing. The gears of this unit are adapted to be meshed with gears 4I and 56, duringmov'ement of the unit toward the final position'at which it is secured to the main casing I5. Thus the unit can be easily and quickly applied or removed.

The unit carries -the=output shaft fl'lyand clutch' mechanisms by which said s'h'aitoan be driven by either engine. One advantage of the structure of the unitis that some of the elements contained in it are interchangeable, being substantial duplicates of one another. Another advantage is found in the mounting structure of the output shaft 31. The bearing structures of this output shaft are formed on a cover whichhes a gear pump therein.

One form of gear train has been *indieated in Fig. 1 and previously described. In the preferred form spur gears 4| and 50, (which may bespiral gears) are driven respectively (see also Fig. 1) by shaft 38 of the mainengine, and shaft 41 of the auxiliary engine.

Referring to Fig. 4, the tower casing I4!) is detachably secured to the top of the main casing I 5 by suitable bolts I4I, but however secured it can simply be lifted off to disconnect its gear mechanism from gears 4i and 50,and give accessto the interior of the main casing. Assembly is equally simple. The main casing I5 has an opening I42 in its top wall and the tower casing is open at its bottom as at I43, and thus when assembled there is a continuous chamber formed by the main and tower casings, the chamber extending the full height of both. When the casing I is removed the elements in the main casing I5 can be easily inspected.

Journalled in the casing I46 are two axially aligned shafts I45, I46. Each shaft is supported at its inner end on a roller bearing, the said bearings being respectively indicated I41, I48, said bearings being held in a suitable cross member I49 supported by opposite walls of casing I46. Each shaft I45, I46 is also stepped at its outer end in a roller bearing and these bearings are respectively indicated I50 and I5l, and each of these bearings is held in a removable bearingcarrying structure. These structures are substantially identical and therefore only one is described in detail and the same numerals are applied to each.

The bearing I58 is held in a tubular extension I53 of the bearing-carrying structure I54, which is received in an opening of the upright wall of the casing I48. The support I54 is suitably secured by bolts. This support I54 is provided with communicating oil channels I55 leading to the shaft I45. These channels are in communication with a downwardly slanting channel I56 leading from a cup I51 formed integrally with and on the inner side of the upright wall of the tower casing. This cup is drip-fed from an oil-drip opening I58 leading downwardly from a horizontal cross-channel I59 at the top of the tower casing and this cross-channel communicates with the output side of a pump chamber of a pumping structure described below, see 5, by means of a channel I shown in dotted lines. Leading from channel I59 are other oil-drip openings IBI I 62 which deliver oil downwardly to the gears and shift mechanism now to be described. The unit structures which include the output shaft 31 and its mounting and driving means "as well as the oil-pump arrangement are features of the invention.

Each of the shafts I45 and I46 has an exteriorly toothed clutch disk fix'ed thereto. The disk of the shaft I45 is indicated at I66. Keyed to the shaft I45 as at I61 is the elongated hub I 68 of a'bevel gear I69. Rotatable on this hub is theelongated hub IIll of a spur gear III which meshes with the gear 50 drivenfrom'tneauxilia'ry engine by shaft-4I. Axiallyshiftable on but nonrotatably secured to the hub I10 is an interiorly toothed, peripherally grooved clutch ring I13 held against rotation on the hub I18 as at I14 by engagement of its interior teeth with exterior teeth on the hub I10. The interior teeth of the ring I13 are adapted to clutch in with or engage the exterior teeth of the disk I86. In Fig. 4 such engagement is shown, so that the gear IN is connected to the toothed ring I66 to cause the bevel gear I69 to be rotated through the shaft I45. It will be understood that when the clutch ring I13 is moved to the right to disengage its teeth from the teeth of the ring I66, the spur gear III will idle and no power transfer to shaft 31 by means of bevel gear I88 will occur.

A construction identical with that immediately above described is provided in relation to the gear 4|, which is driven by the main engine through shaft 38. The clutch disk on shaft N33 is indicated at I18. The hub I19 of bevel gear I80 is keyed to the shaft as at I8I. The spur gear I82 meshes with gear M and has its elongated hub I83 rotative on the hub I19 of the bevel gear, and this hub has teeth thereon cooperating with teeth of the shift ring I84 as at I85. The interior teeth of the ring I84 are engageable with the teeth of the clutch disk I18. In the drawing the clutch ring I84 is shown in unclutched position and therefore the spur gear I82 will idle, and bevel gear I80 will not be driven from shaft I46.

Now referring to Fig. 5, which further illustrates the drive for shaft 31, and shows a unit mounting structure for the shaft which facilitates assembly and which is believed to be structurally unique. both in mesh with a bevel gear I81 fixed to output shaft 31 and this shaft 31 is journalled in a roller bearing I88 at a point near the gear I81. The bearing is held in a tubular extension I88 of a pump case I90 detachably secured to the outer side of the tower casing by bolts I9I. The outer end of the shaft 31 is journalled in the roller bearing I95 held in a tubular extension 196 of a cover I81 for the pump case I90, which cover is also held by the bolts NH.

The shaft 31 has keyed to its outer end a fork element I88 of a universal joint, the other element I99 of which (see Fig. 2) is connected to a shaft 200 in turn connected to a universal joint 2M to an input shaft 282 of an intermediate drive mechanism in a casing 203. The intermediate drive mechanism, later described, of the casing 203 is adapted to control the principal power elements of a plurality of accessories which are supported, at least in part, on the casing, and which casing has no connection with the engines, but is mounted on the bus 204, by any suitable structure, not shown. When we use the word accessories we refer to any or all elements used or usable in relation to any kind of automotive vehicle, including electric generators, air conditioning apparatus, fans, pumps, compressors, etc., or any other device or devices which might be operated by the mechanism of this invention.

One of the oil pump gears 2 is keyed to a sleeve 2I2 in turn keyed as at 2I3 to the output shaft 31. The other pump gear 2I4 rotates about a stub shaft 2I5 suitably stepped in the pump casing cover I91. By means of suitable conduits, not all herein shown, oil is drawn from the bottom of the main casing I5, as a sump, and is distributed to the various parts in the tower and main casings.

The grooved clutch rings I13, I84 are shifted The bevel gears I69, I80 are by a mechanism best shown in Figs. 5 and 6. Fig. 6 is schematic, viewing the mechanism from line 66 of Fig. 5. This shift mechanism comprises a horizontal rod 2I6 fixed in openings 2I1 of the walls of the tower casing, I40. Slidable on this rod are a pair of shift members 2I8, each having a fork 2I9 entering the groove of a corresponding clutch ring. At a point on the rod between the shiftable members 2I8 is a shiftable block 220 having a socket 22I which receives the ball 222 of a shift arm 223 secured to a shaft 224 journalled as at 225 in the slanting wall 226 of the tower casing. Springs 233 and 234 are interposed between the block 220 and the shift members 2I8, to obtain positive clutch-in action. A hand lever 221 is fixed to one end of the shaft 22d and is adapted for engagement with notches 228, 228, 230 in an elongated projection 23I integral with the wall of the tower casing. Stops 233 limit members 2I8 at clutch-in positions.

In Fig. 6 the hand lever 221 is positioned in notch 228 as when the auxiliary engine is transmittably connected to the output shaft 31, as in Fig. 4. This lever may be shifted to the middle notch 229 to disconnect all engine power from the shaft 31. When the lever is in the notch 23!) the output shaft is adapted to be driven from the main engine through the gears 4|, I82 and bevel gear I80.

The shaft 31 with its bearings and the pump gears constitute a unit, bodily separable from the tower casing I40, just as the tower casing unit is bodily separable from the main casing I5. Thus, the tower casing and its contained mechanism, as well as the shaft 31 and the pump, are easily separable as units. During separation of the tower casing the gears I1I, I82 are simply raised out of mesh with the gears 50 and M.

COORDINATED CONTROL OF ENGINE CAR- BURETORS An important broad phase of this invention is related to the conception of coordinately controlling the carburetors of two engines so that the carburetor of one of the engines by which that engine is operated for a lower power output, can be overridden to cause carburetor operation of that same engine for higher power output, for augmenting the power of the other engine.

In the present disclosure, three carburetors are shown and claimed, two on one engine, and one on the other, but there is no intention to limit the broader phase of the invention to any particular number of carburetors, since the gist of this phase of the invention is the control of carburetion to override lower power carburetor operation, to obtain higher power carburetor operation, and to coordinate such a control with carburetion control of a second engine.

Another important part of this invention is the method of control of two carburetors by means of a single control element, moving from an initial to a. final position, and vice versa. In this embodiment the control is such that during the first portion of the movement of the control element from an initial to an intermediate position, the valve of the carburetor of a first engine is opened and is operable through the greater part of its power range without causing opening of the valve of the carburetor of a second engine. Then during continued movement of the control element from this intermediate position to final position, the valve of the carburetor of the second engine is opened and is operable through its 

